The present invention relates to the domain of communication networks, and more precisely to the establishment of video-conference in such communication networks.
Several solutions have been proposed to allow the establishment of video-conference between distant communication equipments connected to communication networks.
A first family of solutions offers a full IP (“Internet Protocol”) video-conference by using an Internet protocol (IP), such as H.323 or SIP (“Session Initiation Protocol”) to transmit both audio and video data between audio and video equipments of distant users over an Internet network.
Such solution family works well but its use is generally restricted to people familiar to IP network operations through communication equipments such as personal computers (PC). Moreover, the called party must be generally warned in advance of the possibility of being called through the Internet network. More, the medium used to transmit the audio and video being the same, the whole communication is degraded or even stopped in case of problem on the medium.
A second family of solutions offers a mixed IP/telephone video-conference by using simultaneously an Internet network to transmit the video data and a telephone network to transmit the audio data.
One solution of this second family is described in the patent document US 2002/0083462. It consists in using, both on the calling and called user sides, apparatuses merging a standard telephone, a digital camera and a display means, and connected to a standard telephone network (or POTS for “Plain Old Telephone Service”) and to an Internet network (through the POTS network (for instance with the so-called ADSL (“Asymetric Digital Subscriber Loop”)), or through a cable network). The apparatuses establish a video communication by transmitting one to the other short data bursts comprising their respective IP addresses, over the POTS network.
This solution is convenient for the users because the video-conference establishment is managed by their dedicated apparatuses. But it requires that each user be equipped with the dedicated apparatus.
Another solution of this second family is described in the patent document WO 03/092287. It consists in using the telephone of a client, connected to a POTS network, and also equipped with an IP communication equipment, to initiate an audio communication requiring the establishment of a video-conference with it. Then the call center transmits a dedicated web page to the client IP communication equipment in order to collect information on the client and its audio and video equipments and to control the establishment of the video transmission over the Internet network in parallel with the audio transmission over the POTS network. The phone call of the video-conference is started from an integration server of the call center by means of an Internet call management server, a computer telephony server and a phone switch.
With such a solution the user only requires a small knowledge of the Internet world and does not require any dedicated equipment. But this only allows a video-conference between a user and a call center, and not a user to user video-conference. Moreover, this solution does not allow either to the calling user or to the call center to start in a pure audio mode (without video) and then to decide at any moment to continue in a video-conference mode with both audio and video data transmission.